Control



1943: c. F. KETTERING EIAL 2,456,198

CONTROL Filed April 7, 1944 2 Sheets-Shet 1 3nnentou' 1948. c. F. KETTERING EIAL 2,456,198

CONTROL Filed April '7, 1944- I 2 Sheets-Sheet 2 Patented Dec. 14, 1948 '(IONTR'OL Ehal le'S iF. Kettering :and Albert Fischer, De-

troit, .Mich assignors to General Motors" Gor- ,poration, Detroit, Mich, a corporation of Dela- Ware Application April '7, 1944, "Serial No. 529,990

There-are many instances in which under certain desired. conditions it may ;=be. necessary :to, operate certain controls, namely, such instances where for safety purposes certain switches 'must be closed upon atmospheric or other pressures reaching either -too "high or too :low a value. There are other instances of the same import wherein it is desired toiclose switchessdepending upon atmospheric pressure changes :and as (one example of thismay-bementioned aircraft which are designed to be flow-neither entirely :alone without manual controltor "byyra'dio control :f-rom some distant point, in such equipmentas aerial torpedoes for example. .In the latter case it would be necessary to provide some means for causing th'e torpedo to climb-to 5a oertainaltitude, and'whenit reached the latt'enilevel offiand fly for a predetermined'time or distance.

it is therefore "an object 'of our invent-ion ---to provide pressure responsive means :for controlling ."the rate-of climb of 'aniaircraft.

It is a furtherrobject of our'invention-toiprovide presettable means ::for controlling the "rate ofsclimb of an aircraft and also the-zelevation at which the latter is designedlto:levelioff:torwdistant flight.

It is a still further object of our= invention :to rovide pressure-responsive :meansiactuaitable "by atmospheric .pressure for controlling the {rate of climb 'of an aircraft which may-be adjusted.

Withlthese :and otherobjects view which will become apparent as the specification proceeds, the embodiments of our invention-will be best understood :by reference ato "the following specification and claims 'and the illustrationsqin the acc'ompanyin'g drawings, in' which:

Figure 1. shows aside elevation partly in=sectionrof an aerial torpedo in which -.;our@control or pressure-responsive device is :mounted;

Figure 2 shows an enlarged vertical section through the "control mentioned above;

Figure 3 is a sectional view-ofthecontrol taken on line 33 of Figure2;

Figure 4 is a partial section off-a portion-of -jthe control taken on line 4-4 'of Figure 2.;

Figure 5 is a still'further enlargedverticalfsectiontaken on-line 5.-'t5 of F-igure:,3.; -;and

Figure 6 is a 'sch'ematicwiring :diagrarmofrthe control system for anautomatically flown:plane including our pressure 01 altimeteraresponsive control.

2 Referring g-nowinore specifically to the draw- -ings,,:there isshoWn-in-Figure 1 an aerial torpedo '2 "having mounted therein an altitude control, indicated generally -at 4,:which controls an elevatorimotor 6 for varying the position of the ele- Nators 8 and to which is connected a feedback or follow-up means it The altimeter "or altitude iciontrolling means :consists of a casing formed of 'twoipar ts '12 and :i6,-the upper; portion beingof drums-shape and being :held upon the lower {part by :a bent spring i8xpassin' *over the top {and vremovable for inspection :or adjustment of the interior parts. -A-;m ounting plate '26 is provided in the lower part of Zthe casing. This plate :has aidiacentcne end upstanding ears 2| through which ipointed horizontal ;-mounting screws H pass to project into openings =19 in ears 2-3 of a,:pivotally=mounted plate 22 :so that theasame may ibe secured {in hinged relation thereto,

,Pivotally mounted plate :22 has :secured to its underesurf-ace Jan aneroid -;pr'essure element .24 which is the operating element *otour device. Secured te -the upper face f 26 1of 4 the aneroid elementis :a;hol1ow stud 28, :the upper surface-of which is threaded and extends above the :upper surface of the :pivoted plate-22,;and';being1locked theretmby'nm 30. Theqextensionronqthehollow studspr'o'vides a'connection-for exhausting the air therefrom. In alignment with thjegstud 2s and extending from the lower surface 32 {of (the aneroid pressure element is a sec0nd.=operating threaded 'stud 34 having a central diametral slot 3-36 therein whichis adapted to carrya-Etransvierse spin 3 8 1 whose vertical position may -=be adiustedby a nutzdfl'threaded on the :stud.

gijkcross :the bottom .of the ;:ane1'oid bellows :extends ';a composite element, ;-half of which is formed of ;-a :flat i-spring member 42, onetend of which isiclamped as shown at :44 to the router end= of .the ipi-voted member 22 andwhich has. a centralxsiot Ahstraddlinathe stud fi th-and the opposite end I of which :is rigidly secured to rod 48 which (extends -to a' position approximately under the pivot V-of themember =22. Mountedion the=ears ;23qand.in the openings t9 ere-pointed pins -50 "which project toward each other and pivotally-support r-therebetween --.a short v:shaft 52 which ;=rnay "be readily rotated on -these pivot points. rOn-zthis shaft .is frictionally r mounted ==a lever -54 of :electrically insulatingematerialvin(operatively non rotatingrelation withrespect-ito the shaft. An iaxially-zspaced-ipin .56 :extendsthroug-h the ';shaft andris secured thereto.

:The irmer :end @of thezlOd 48 oarr i-esq-therein a U-shaped spring member 58, one end of which is secured in a transverse opening in the rod and the other leg proceeds up through an adjacent slot 60 in th rod and may have its axial position altered by an adjusting screw 62 threaded therein. The upper end of this spring member 58 is adapted to contact th extending end of the pin 56 whereby any vertical movement of the inner end of the rod 48 will cause the stub shaft 52 to be rotated. The shaft 52 is spring biased by convolute spring 53. Since the leaf spring 42 normally causes this member to assume its lowest possible position, this position will be determined by the transverse pin 36 and therefore by the condition of the aneroid pressure element 24.

The lever 54 has extending through its outer end one end of a rod 64 which is supported thereby and extends up into engagement with an adjustable contact 66. This contact 66 is in the form of a pin projecting from a traveling nut 66 on a threaded shaft I which is supported in flanged ears 60 on an extension from a substantially circular pivotally mounted member I2 which also supports a clock or other time mechanism I4. The threaded shaft extends through the upper ear 69 and carries at the upper end a knurled head I6 for manual adjustment of the traveling nut 68. An indicating scale I! callbrated in feet elevation is provided to permit setting. Supporting means I2 also is provided with a substantially horizontal platform I8 which carries a pair of switch arms 80 and 82 whose purpose will be later described.

Projecting in the opposite direction from the rear face of the same portion is a similar platform 83 which supports a substantially vertical threaded shaft 84 having a manual engageable knurled head 86, the lower portion of which is rotatably mounted in a short stub shaft 88 in an upstanding ear 90 on the supporting plate 20 so that when the head 86 is turned, the position of the vertical mounting plate I2 with respect to the horizontal mounting plate 20 may be adjusted abIut an axis approximately in alignment with shaft 52. There is provided also on the face of the time mechanism an arm 92 adapted to be rotated by the same and to engage the end of arm 64 and also switch arm 82 and open the switch provided by the two arms 80 and 82 under certain conditions.

On the rear face of the timing mechanism there is mounted a control solenoid 94 to whose armature 96 is secured a locking mechanism 98 adapted to control the operation of the time mechanism by engagement with an operating wheel I00 thereof. There is also provided a follow-up mechanism whereby if the control calls for a change in the position of the elevators or other controlled equipment, the operation of the motor 6 to provide this variation will at the same time alter the position of the aneroid mount with respect to the control mechanism and prevent over-travel. This follow-up is provided through flexible transmission cable it! which has its inner end swedged into a collar or coupling I02, which is in turn, connected to a rotatable rod I04 having thereon a cam I05. This cam is adapted to engage a roller I03 secured to the forward under-surface of the pivoted platform or plate 22, this latter construction being best shown in Figure 4.

Thus, any change in the atmospheric pressure, and therefore in the pressure element 24, will cause the stud 34 to be moved, permitting the rod 48 to move up or down depending upon the pressure change which through the spring 58, pin 56,

shaft 52 and arm 54 will cause th arm 64 to be moved substantially in a circular arc. When this arm 64 contacts 66, a circuit is completed for control purposes.

Referring now more specifically to Figure 6, there is shown therein a complete control system for automatically operating an aerial torpedo in which our altimeter control has been incorporated. The motor I In in the upper left-hand portion of the diagram is adapted to operate the rudder control, and therefore if the reversing switch [I2 connected thereto is in one position, the motor III] will run in one direction, and if the switch i in the opposite position, the motor will run in the opposite direction, thus adjusting the rudder or course of the aircraft. This switch I12 is controlled by a combination gyroscope and compass means, the gyroscope being indicated generally at H4 and the compass at H6, which control the relay H2 through a power amplifier H8. This particular portion of the apparatus forms no part of the subject matter of this application, but is disclosed in a copending application in the names of Kettering and Fischer, Serial No. 458,358, filed August 3, 1942, now abandoned, and serving only the purpose of illustrating how applicants present invention is incorporated therewith to provide automatic control for an aerial torpedo. It will be sufficient in this instance to state that the gyroscope and compass do control the upper relay l I2 which in turn controls the rudder motor I I0 to direct the course of the aircraft.

In like manner, the altimeter control 4 controls the operation of the elevator servomotor I20 through a reversing switch relay I22 which is controlled through a power amplifier I24. To complete the circuit diagram, a synchronous vibrator I26 and a source of D. C. power l28 provide the supply of power necessary for the various portions. A switch I30 is placed in the main line to the clock or time control means to prevent the same from operating prior to actual taking to the air of the craft and is placed on the bottom of the craft so that the weight thereof keeps this switch open, but as soon as it takes off, the switch is allowed to close. This permits the elevators to be adjusted to a desired position and to remain there until the craft actually takes off. Master switch I32 also cooperates in maintaining the system deenergized until the proper moment.

The object of the device as set forth previously is to control the plane so that it will climb at a definite rate to a preset elevation and then level off for continuous flight at that level or altitude. It is a hunting system as the control motor is at all times operating in one direction or the other as controlled by the biased reversing switch I22.

In operation the knob 16 is first turned until the index mark on traveling nut 66 is opposite zero on scale 11. Knurled knob 86 is then turned to adjust pivoted frame I2 until arm 04 whose position is determined by the aneroid means is just in contact with the pin 66. This is with the cam I06 in a position corresponding to horizontal elevator position. This corrects the device to the altitude of the location of operation which may vary considerably. Knob I6 is now turned to adjust the nut 68 to read the altitude above ground level, at which it is desired to have the plane level off, say, for example, 2000 feet. The clock mechanism is next set by pulling out stem I34 and setting arm 92 just out of contact with arm 64. The clock mechanism will not operate inasmuch as interlock 98 is in engagement with wheel I00.

The plane is then started and launched and as it takes to the air, switch I30 closes energizing relay 94 and setting the clock in motion. As the plane has had its elevation set at a desired position, it starts to climb, and as it does, pressure in the aneroid is reduced, tending to cause arm 64 to move in a clockwise direction as viewed in Figure 2. If this movement is faster than the movement of the clock arm 92, which is now also moving in the same direction, as it probably will be, as soon as it contacts the latter the circuit through arm 64 will be grounded and conductivity of tube I24 interrupted to deenergize the relay coil in relay I22 and cause the contacts and motor to reverse. This reverse movement of the controls, and therefore of the follow-up means through the cam I06, will cause the arm 64 to be backed away and the contact between arms 64 and 92 to be broken. The ground will be removed from grid I38 of tube I24 and the same may now conduct, energizing the relay coil I40 and again reversing the motor I29. This hunting process will be continued, the clock-operated arm 92 gradually letting the aneroid-operated arm 64 down at a definite determined rate to provide a given rate of climb. When, however, arm 64 has proceeded to a point where it engages the preset pin 66, it no longer can descend but will contact and break with this pin from this time on to maintain the plane at this preset elevation level.

The arm 92 merely proceeds along its course until it engages arm 82 and opens the switch 80, 82 to again deenergize the relay 94 and lock the clock mechanism against further operation.

In this design the problem of inertia of the parts was taken into consideration and it is desired to point out that by mounting the aneroid spring and contact arm below the diaphragm, as above described, the inertia efiects thereof due to leveling off or air pockets provides a stabilizing influence on the plane being controlled, whereas if they had been located on top of the diaphragm, our experience indicated that their inertia would increase hunting.

It will thus be evident that we have provided means that may be preset before launching to de: termine a definite rate of climb of the craft to a given elevation and then maintain it at that level.

We claim:

1. In control means, a pivotally movable switch arm, pressure-responsive means for moving said arm about its pivot, a pivotally movable abutment in the Path of movement of the arm, timing means for progressively moving the abutment, and a second adjustable abutment in the path of the pivoted arm to limit its extent of movement.

2. In control means, a base, a pivotally mounted support on said base, pressure-responsive means carried by said support, an arm pivotally mounted on said support effectively coupled to said pressure-responsive means whereby the latter determines the position of said arm, an adjustable abutment in the path of said pivoted arm to prevent its movement past a desired point, and a timed progressively moving abutment in the path of the arm to determine the rate at which it approaches the first-named abutment.

3. In control means, a base, a pivotally mounted support on said base, pressure-responsive means carried by said support, an arm pivotally mounted on said support eifectively coupled to said pressure-responsive means whereby the latter determines the position of said arm, a second pivotally mounted support on said base, an abutment adjustably mounted thereon in the path of movement of the arm, and means for adjusting the position of the second pivotally mounted support.

4. In control means, a base, a pivotally mounted support on said base, pressure-responsive means carried by said support, an arm pivotally mounted on said support effectively coupled to said pressure-responsive means whereby the latter determines the position of said arm, a second pivotally mounted support on said base, an abutment adjustably mounted thereon in the path of movement of the arm, means for adjusting the position of the second pivotally mounted support, time-controlled means mounted on said second support and a progressively movable second abutment driven by said timed means adapted to move in the path of movement of the arm and control the rate of progress of the arm toward the first abutment.

CHARLES E. KETTERING.

ALBERT W. FISCHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,378,740 Walkup May 17, 1921 1,420,348 Swift June 20, 1922 1,557,093 Roesch Oct. 13, 1925 1,869,161 Merrill July 26, 1932 1,914,771 Eggleston et a1. June 20, 1933 2,246,186 Prince June 17, 1941 2,324,164 Kronmiller July 13, 1943 2,387,562 Brunot Oct. 23, 1945 

